F engine info wanted

tom3

Lawn Addict
Joined
Apr 9, 2018
Threads
25
Messages
1,579
I've had this LB for a year now, 21" with the F engine, new coil, pulled muffler and ports were clean, tune up, clean and lubed everything. Runs pretty good, a bit on the rich side due to carb shaft wear I suspect. Just curious about the internals of the motor. Does this little engine have roller bearings on the crank? Rod journal? Is there a recommended rpm for power and life? Does the cylinder have an iron sleeve? No non-ethanol gas around here, should I use mid grade or better gas? I got a case of lawnboy oil and mix as listed, seems like some extra oil but I'll stick with what they say. Thanks.
 

Lawnboy77

Well-Known Member
Joined
Apr 18, 2016
Threads
1
Messages
193
Yes the F series has needle bearings throughout. Top and bottom of crank and both ends of connecting rod. The cylinder also has an iron sleeve.

It is recommended to run at 3200 rpm max. The fuel grade I run is high octane, just seems to be less ethanol in the high grade.

They are good little engines! I currently have 3. The only problems I’ve had in the last couple years have been bad aftermarket coils. The problems I experienced was 4 cycling at around 2700. I got frustrated with it and decided to try OEM and the problem was solved. By the way, those new OEM coils from Germany rock!
 

Lawnboy77

Well-Known Member
Joined
Apr 18, 2016
Threads
1
Messages
193
Those are the official Lawn-Boy modules. I suppose Toro has contracted a German company to make their coils for them. I ordered them from Partstree.com. There might be a cheaper option out there that is still a quality module, but I definitely won’t do the made in China eBay specials again.
 

tom3

Lawn Addict
Joined
Apr 9, 2018
Threads
25
Messages
1,579
Thanks for the info. Pretty well built for such a simple engine I'm thinking. The first coil I bought (Ebay) didn't fit right, had to really rig it up to fit and work. Decided to do it right and put on a Lawnboy replacement. 16 degrees here this morning, might not need the mower for a while.
 

Boobala

Lawn Pro
Joined
Feb 15, 2015
Threads
200
Messages
7,000
Thanks for the info. Pretty well built for such a simple engine I'm thinking. The first coil I bought (Ebay) didn't fit right, had to really rig it up to fit and work. Decided to do it right and put on a Lawnboy replacement. 16 degrees here this morning, might not need the mower for a while.

Ya can't mow the snow ..??? sounds 2 me like ya got a LAWN-GIRL, instead of a LAWN-BOY !! you must B mixed-up with all this gender hooplah goin aroun.. :laughing:..:laughing:..:laughing:
 

Russ2251

Well-Known Member
Joined
Mar 27, 2018
Threads
1
Messages
341
...a bit on the rich side due to carb shaft wear...
This would cause a lean condition.
got a case of lawnboy oil
Any TC-W3 (factory recommended) oil will work as well as Lawn-Boy oil and is generally less expensive.
 

tom3

Lawn Addict
Joined
Apr 9, 2018
Threads
25
Messages
1,579
Ya can't mow the snow ..??? sounds 2 me like ya got a LAWN-GIRL, instead of a LAWN-BOY !! you must B mixed-up with all this gender hooplah goin aroun.. :laughing:..:laughing:..:laughing:

Where do I get that Lawn Girl? Probably mow me right into bankruptcy.
 

tom3

Lawn Addict
Joined
Apr 9, 2018
Threads
25
Messages
1,579
This would cause a lean condition..

I kind of know my way around carbs but guessing here. This carb and the block inlet manifold area has a small port direct into the crankcase, the throttle shaft has a hole in it that matches up to that port, opens up the hole at full throttle and bleeds mixture from the cc back into the carb inlet. With the shaft worn I suspect the bleed is blowing by all the time. Carbs are sure expensive for the Lawnboys. No $16 carbs - like for about everything else seems like. Runs good enough as is, little cackle on a two stroke is music anyway.
 
Top